I have to install the XSLT processor on my Apache 2.0.48 + Php 4.3.4

I read that I have to recompile the php with the xslt (sablotron) but I don't know how to do it.
If I rebuild the php, the actual websites in my server can had problem or the xslt adding cannot modify the current functionality of the system?

I have to use the xslt for a new virtualhost that want this processor.

Can anyone explane me how to installing this processor??

THX to all for your help and for your replies

Andrea